metamorphic
Quartzite river stone
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: light gray-white; Luster: vitreous to dull; Structure: granoblastic/granular; Cleavage: none (conchoidal fracture).
- Hardness
- 7 on Mohs scale
- Color
- light gray-white
- Luster
- vitreous to dull
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: light gray-white; Luster: vitreous to dull; Structure: granoblastic/granular; Cleavage: none (conchoidal fracture).
Formation & geological history
Formed from the metamorphism of quartz sandstone under heat and pressure. This specimen is a water-worn river pebble, likely millions of years old based on the recrystallization process.
Uses & applications
Used in construction, as road ballast, in glass manufacturing, and as decorative landscape gravel or tumbling media.
Geological facts
Quartzite is so durable that it often outlasts the mountains it was formed in, becoming rounded pebbles in stream beds that can travel hundreds of miles over millennia.
Field identification & locations
Identify in the field by its hardness (it will scratch glass) and lack of reaction to acid. Commonly found in riverbeds, glacial deposits, and mountain outcrops globally.
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